A missing portrait by Vincent Van Gogh was valued at as little as $80 by a Tokyo auction house this week - before the mistake was discovered.

The Shinwa Art Auction Company was planning to auction off the small portrait of a peasant woman for between 10,000 and 20,000 yen ($83 to $167) after struggling to establish the identity of the artist.

Van Gogh sold just one painting during his own lifetime and largely lived in poverty His Portrait of Doctor Gachet was sold for $82.5m to a Japanese businessman in 1990, becoming the most expensive work of art in history

But a last-minute fax from the Van Gogh Museum in Amsterdam confirmed that the picture was an early work by the Dutch impressionist master, boosting its value to at least $25,000.

"We just didn't know," said Shinwa's president, Yoichiro Kurata, as he announced that the auction would go ahead on Saturday with the new starting price.

"We didn't think it was the real thing."

But the oil painting, 41 centimetres (16.4 inches) high by 35 cm (14 inches) wide, proved to be the genuine article.

'Over-restored'

When it came to the auction house as part of the collection of the late Japanese painter Kazumasa Nakagawa, it aroused Shinwa's suspicions as it resembled catalogued works by Van Gogh.

Mr Kurata sent it to the Van Gogh Museum in January and received a faxed letter back on Thursday saying that "Peasant Woman" was an original, painted some time between 1884 and 1885 in Nuenen, in the Netherlands.

The auction house's managing director, Shinji Hasada, said that the painting could actually fetch up to 30m yen ($250,000) but he pointed out that some over-zealous restoration work had affected the value.

Van Gogh Museum paintings curator Louis van Tilborgh said in his report that the work had "lost most of its original character and Van Gogh's characteristic brushstrokes are only partially recognisable".

The portrait was one of about 170 pieces of art in the auction from the collection of Nakagawa (1893-1991), an admirer of Van Gogh and French impressionist giant Paul Cezanne.